To win back his old job, the former Republican governor of Maryland has set his sights on an unlikely target: the Democratic bastion of Montgomery County.

Despite lackluster performances there in his previous two bids, Robert L. Ehrlich Jr. is betting that anxiety about the faltering economic recovery and discontent with the status quo will penetrate even a left-leaning jurisdiction that is home to more federal workers than any other in the state.

Ehrlich, who plans to campaign again in Montgomery on Tuesday, has mapped a strategy that in part seeks to win votes in the western and northern parts of the county, which are more conservative than the communities that hug the Capital Beltway. He hopes a message of lower taxes and a friendlier business climate will sell in a county that has an increasingly diversified private sector.

"This is the type of election cycle where Democrats are more willing to cross party lines," Ehrlich said as he took a break recently from greeting seniors arriving at the county fair in Gaithersburg. "We think the low 40s is doable here."

That might not sound terribly ambitious, but in Maryland's largest county even a modest uptick in Ehrlich's support could add thousands of votes to his statewide total in what is shaping up as a competitive rematch against Gov. Martin O'Malley (D).

Ehrlich won 38 percent of the vote in Montgomery in 2002, when he became the first Republican in a generation to win the governorship in Maryland. His share dropped to 37 percent against O'Malley in 2006. Two years later, Sen. John McCain (Ariz.), the GOP presidential candidate, managed 27 percent.

Even Ehrlich advisers say that, by itself, improvement in Montgomery isn't likely to be enough to send Ehrlich back to Annapolis. Some analysts say his time would be better spent campaigning elsewhere.

There appears to be room for growth: Given its size, Montgomery is home to more registered Republicans - 122,189 as of last month - than any other Maryland jurisdiction but Baltimore County, which had 4,000 more. And it has nearly as many registered independents - 120,938 - as Republicans. Together, those two groups account for about 43 percent of its electorate.

Some more liberal Republicans have been elected to represent parts of Montgomery, most notably Constance A. Morella, a longtime congresswoman.

O'Malley advisers say they don't expect a repeat of that scenario. O'Malley, a former Baltimore mayor who grew up in Montgomery and has relatives there, has become better known in the racially diverse jurisdiction only since defeating Ehrlich four years ago, they say.

"Families in Montgomery County understand that Bob Ehrlich is out of touch and that his empty promises today stand in stark contrast to his failed record as governor siding with George Bush and special interests time and time again," said O'Malley spokesman Rick Abbruzzese.